Offer a lightweight anonymous communication option

Ideally we can create ad-hoc URLs to a chat room hosted by a third party which we give to author and codechecker. This URL is then shown to both author and codechecker (and editor, of course).

- https://voidchat.org/
- https://voidchat.org/v/codecheck-ojs-491309949984151286
- https://otr.to/ (no history, browser tab must be open... could still work?)
- research PHP chat server implementations

**Alternatively**, see if it is possible to turn the "Discussion" feature within OJS into an anonymous chat, see https://docs.pkp.sfu.ca/learning-ojs/reviewer/en/#review-discussion Maybe the chat can be linked as a discussion at least?

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**User story:**

- _As an editor, I want my authors and codecheckers to now know each other but still facilitate a low threshold direct communication between the two roles._
- _As a codechecker, I want a way to quickly as the author questions to resolve issues with the reproduction, without breaking the anonymity requirements by the journal._

This is a strategic feature to lower the barriers for "old school" journals.
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## Related User Stories

- **A-SO1** (direct): As an author, I want to opt in to a CODECHECK during submission and communicate with the codechecker...
- C-CO1 (related): As a codechecker, I want the plugin to present the appropriate communication channel...
- C-CO3 (related): As a codechecker, I want to start a discussion with the author from within OJS...
- E-SO1 (related): As a handling editor, I want to see the CODECHECK status, the discussion thread...

_User story references from the [CHECK-PUB User Stories document](https://codecheck.org.uk/pub/)._